The present invention relates generally to portable shelters. Portable shelters such as tents provide a temporary, relatively quickly erected shelter from the elements. Traditional tents typically feature a flexible fabric floor and walls that are supported by an internal or an external frame. Tents may be utilized for recreation or in other situations, such as by military personnel or by medical personal. Tents are often erected on uneven ground. As tents often include flexible fabric floors, this can result in an uneven surface inside the tent, even if care is taken to clear or smooth out an area before erecting the tent. Tents are often used with an additional ground sheet formed of a rugged, moisture-resistant material disposed between the tent and the ground. While such ground sheets can provide a barrier between the tent and moisture in the ground, any precipitation or accumulation of liquid on the ground is unable to pass under the tent and is forced to flow around or through the tent.